A proanthocyanidin consisting of two molecules of (−)-epicatechin joined by a bond between positions 4 and 8' in a β-configuration. Procyanidin B2 can be found in Cinchona pubescens (Chinchona, in the rind, bark and cortex), in Cinnamomum verum (Ceylon cinnamon, in the rind, bark and cortex), in Crataegus monogyna (Common hawthorn, in the flower and blossom), in Uncaria guianensis (Cat's claw, in the root), in Vitis vinifera (Common grape vine, in the leaf), in Litchi chinensis (litchi, in the pericarp), in the apple, in Ecdysanthera utilis and in red wine.

InChI=1S/C30H26O12/c31-13-7-20(37)24-23(8-13)41-29(12-2-4-16(33)19(36)6-12)27(40)26(24)25-21(38)10-17(34)14-9-22(39)28(42-30(14)25)11-1-3-15(32)18(35)5-11/h1-8,10,22,26-29,31-40H,9H2/t22?,26-,27?,28?,29?/m1/s1

Procyanidin B2 (PB2) is a naturally occurring flavonoid widely found in cocoa, red wine and grape juice, PB2 could protect against oxidative stress- and chemical-induced injury in colonic cells by modulating the endogenous cellular defence, PB2 protects against oxidative injury in colonic cells and up-regulate the expression of GSTP1 via a mechanism that involves ERK and p38 MAPK activation and Nrf2 translocation.[1]
Procyanidin B2 (PB2) is one of phenolic compounds in apple pomace, an agro-industrial byproduct in apple juice processing, PB2 at no less than 50 mu g.mL(-1) could significantly suppress inflammation in the LPS-induced cells, shows that high pure PB2 prepared from apple pomace has a remarkable anti-inflammatory property.[2]
Procyanidin B2 exhibits cytotoxic activity to MCF-7 cells and it could be a potential antineoplastic agent. [3]
Procyanidin B2 has toxic property towards triple negative breast cancer cells, it may shows new promise for therapeutic intervention of cancer.[4]
Procyanidin B2( PB2) is absorbed and excreted in urine, and a portion of the PB2 is degraded to (−)-epicatechin and to the metabolized conjugated and/or methylated (−)-epicatechin internally in the rat, PB2 also can reduces the accumulation of lipid peroxide in plasma oxidized by copper ions.[5]
Procyanidin B2 and a cocoa polyphenolic extract inhibit acrylamide-induced apoptosis in human Caco-2 cells by preventing oxidative stress and activation of JNK pathway.[6]
Procyanidin B2 has anti- and pro-oxidant effects on metal-mediated DNA damage by interacting with H2O2 and metal ions.[7]

English website: Procyanidin B2
Japanese website: Procyanidin B2
Chinese website: Procyanidin B2

[1] Rodríguez-Ramiro I, Ramos S, Bravo L, et al.Eur J Nutr, 2012, 51(7):881-92.
[2] Zhang H, Ying C. Bangl J Pharmacol, 2011, 6(2):106-10.
[3] Avelar M M, Gouvêa C M. Indian J Pharml Sci, 2012, 74(4):351-5.
[4]Shilpi A, Parbin S, Sengupta D, et al. Chem-biol Intact, 2015, 233:122-38.
[5] Seigo Baba, Naomi Osakabe, Midori Natsume, et al. Free Radical Bio Med, 2002, 33(1):142-8.
[6] Ramos S, Bravo L, Goya L, et al. J Nutr Biochem, 2011, 22(12):1186-94.
[7] Sakano K, Mizutani M, Murata M, et al. Free Radical Biol Med, 2005, 39(8):1041-9.
[8] Cheng X G, Wen-Zheng J U, Dai G L, et al. Pharm Clin Res, 2013, 21(01):39-41.